Review

The usage iterates over a data stream to encrypt all values fetched from it. During the iteration, the same Cipher instance is reused for the encryption tasks---which is fine---, but it is also reinitialized with each iteration. Cipher does not support reinitialization and, hence, this may lead to erroneous encryption.

The init() call should happen before the loop.

• superfluous/iteration

mubench/examples/jca/ReinitializingCipher.java

misuse(BufferedReader, Key)

class ReinitializingCipher {
    List<byte[]> misuse(BufferedReader dataStream, Key key) throws NoSuchPaddingException, NoSuchAlgorithmException, IOException, InvalidKeyException, BadPaddingException, IllegalBlockSizeException {
        Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
        String line;
        List<byte[]> encryptedData = new java.util.ArrayList<byte[]>();
        while ((line = dataStream.readLine()) != null) {
            cipher.init(Cipher.ENCRYPT_MODE, key);
            encryptedData.add(cipher.doFinal(line.getBytes("utf-8")));
        }
        return encryptedData;
    }
}

public class ReuseCipher {
    List<byte[]> misuse(BufferedReader dataStream, Key key) throws NoSuchPaddingException, NoSuchAlgorithmException, IOException, InvalidKeyException, BadPaddingException, IllegalBlockSizeException {
        Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
        cipher.init(Cipher.ENCRYPT_MODE, key);
        String line;
        List<byte[]> encryptedData = new java.util.ArrayList<byte[]>();
        while ((line = dataStream.readLine()) != null) {
            encryptedData.add(cipher.doFinal(line.getBytes("utf-8")));
        }
        return encryptedData;
    }
}